Atlantic ocean circulation slowdown intensifies tropical cyclones in the North Atlantic

doi:10.21203/rs.3.rs-5147082/v1

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Atlantic ocean circulation slowdown intensifies tropical cyclones in the North Atlantic

https://doi.org/10.21203/rs.3.rs-5147082/v1

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The slowdown of the Atlantic Meridional Overturning Circulation (AMOC) is ubiquitous in climate projections, representing a major risk of global warming with far-reaching climatic impacts. Here, we investigate how the future AMOC slowdown can affect the activity tropical cyclones (TCs). To that end, we compare two sets of global warming simulations: one that exhibits AMOC weakening and another in which AMOC intensity is fixed. Using these experiments, we compute Genesis Potential Indices (GPI), to assess large-scale ocean-atmosphere conditions for TC formation, and conduct downscaling TC simulations for the two scenarios. Our analysis shows strongly enhanced tropical cyclogenesis in the North Atlantic, especially along the U.S. eastern seaboard and in the Gulf of Mexico, in a warm climate with a weakened AMOC. The AMOC slowdown causes roughly 60% of the estimated seasonal increase of 12 storms in the Atlantic with warming. Higher TC potential intensity (PI) in the North Atlantic due to greater air-sea thermodynamic disequilibrium and, to a lesser extent, reduced vertical windshear explain these findings, which highlight the important role of AMOC slowdown in 21st -century TCs.

Earth and environmental sciences/Climate sciences/Atmospheric science/Atmospheric dynamics

Earth and environmental sciences/Natural hazards

Earth and environmental sciences/Climate sciences/Ocean sciences/Physical oceanography

Tropical cyclones inflict extensive damages in coastal communities globally, costing in the U.S. alone some $400 billion between 2004 and 2017 (1, 2). Thus, understanding how TC activity could change in a future warmer climate is critical, especially because coastal urbanization trends could exacerbate TC risks associated with strong wind, heavy rainfall, and storm surge (3-6). Although some coastal regions are projected to experience an uptick in TC-related damage in a warmer climate, the projected change in global TC frequency in a warm climate remains uncertain; some studies project an increase in TC activity (7, 8), while others project a decrease (9-12) or no change, which is influenced by climate model (GCM) parameterizations and biases (13-17). The projected trends are also basin-dependent, since each ocean basin is uniquely impacted by the change in atmospheric and oceanic circulation associated with a warmer climate (13, 17-21).

The Atlantic Ocean will be especially affected by changes in the Atlantic meridional overturning circulation (AMOC) – an ocean circulation system that transports warm surface water from low to high latitudes and carries cold water back at depth (22). The AMOC is projected to weaken in a warming climate due to enhanced upper-ocean stratification and suppressed sinking of cold surface water at high latitudes (23-25). A potential AMOC collapse could impact atmospheric circulation and tropical thermodynamic conditions critical for TC genesis and propagation (26-28). While current GCM simulations agree that AMOC collapse is unlikely, they all project an AMOC weakening, albeit with a large uncertainty in the slowdown rates (23, 29, 30).

Several studies examine the relationship between AMOC variations and TC activity. For example, R. Zhang and Delworth (31) and Klöwer et al. (32) stress that AMOC variability can affect North Atlantic sea surface temperatures (SSTs) and tropical cyclogenesis. Yan et al (33) argue that the decline in major TC activity in the North Atlantic between 2005 and 2015 can be linked to a weakened AMOC. Yan et al.’s study suggests that the AMOC slowdown contributed to an increase in tropical Atlantic vertical wind shear, which is associated with a reduction in TC genesis near the TC main development region. Additionally, Toomey et al. (34) used geologic records to show that a weakened AMOC during the Younger Dryas (12.9–11.7 ka) might have led to higher TC landfall along the southeastern U.S. coastline.

Although these TC changes have been linked tentatively to AMOC variations, the impact of a weakening AMOC on global tropical cyclone activity in a warmer climate remains unclear, and improving predictions in the AMOC circulation can potentially contribute to more accurate TC projections (Chang and Wang (35)). Accordingly, our study aims to better understand the impacts of AMOC weakening on TCs with anthropogenic warming.

To isolate the impacts of a weakening AMOC on future TCs, here we utilize two Representative Concentration Pathway 8.5 (RCP8.5) ensemble simulations from 1850 to 2100 using Community Climate System Model version 4 (CCSM4) (Methods and ref. 36). In the first simulation, hereafter named wk, the AMOC strength steadily weakens through the late 21^st century (Fig. 1a), while the AMOC strength of the second simulation, named fx, is artificially fixed at 1980 levels by gradually removing fresh water in the subpolar North Atlantic. Both simulations experience anthropogenic warming through 2100 (Fig. 1b), slightly higher in the fx case. When analyzing the potential impacts of a weakened AMOC on TCs, we compare the mean 2075-2100 conditions between the two simulations (Fig. 1a and 1b).

Given the coarse resolution of the CCSM4 model and its inability to fully resolve TCs (37, 38), we utilize a Genesis Potential Index (GPI; Methods) as a proxy for TC activity. To compare the projected TC activity in a scenario with a weakened AMOC strength and a scenario with a fixed AMOC strength, both under global warming, we compute the mean GPI from year 2075 to 2100 during the active TC seasons: August through October (ASO) in the Northern Hemisphere, and December through February (DJF) in the Southern Hemisphere. Secondly, we apply a downscaling approach to generate synthetic TC tracks for both scenarios (Methods) to observe TC track and intensity changes as a result of a weakened AMOC. These complementary approaches help describe the differences in projected TC activity between the simulations.

Impacts of AMOC weakening in a warm climate on TC activity: GPI results

To compare the change in TC activity governed by anthropogenic forcing to the change in TC activity governed by a weakened AMOC, we compute the basin-averaged GPI for both simulations during a 26-year historical phase (1980–2005) and during the aforementioned future warming scenario (2075–2100; Fig. 2). GPIs are empirically derived indices combining monthly predictors selected for their importance in TC genesis. We normalize GPI to give a global mean value of 90 annual storms over the early 1980–2005 wk simulation. Comparing storm genesis between the historical and future model simulations suggests a general increase in TC activity due to the net effects of anthropogenic warming (Fig. 2, red bar) in nearly all basins, but especially in the North Atlantic and Western North Pacific basins. Globally, considering the net effects of anthropogenic warming, we observe a projected increase of roughly 30 storms per season, corresponding to a 33% increase in TC activity.

Isolating the effect of the AMOC, we further find that the weakening of the AMOC is the dominant effect in strengthening TC genesis from the fx to wk simulations for the late 21st -century climate (Fig. 2, blue bar) in the North Atlantic and Western North Pacific basins. For example, the effects of AMOC slowdown explain roughly 60% of the projected increase in 12 storms per season in the Atlantic basin in a warmer climate. The effects of AMOC slowdown explain roughly 100% of the storm count increase in the North Indian and Western South Pacific basins in a late 21st century warming scenario (i.e. TC changes in these regions in the fx simulation are nearly zero).

Next, we compare the spatial distribution of GPI during TC active seasons between the wk and fx simulations (Fig. 3a). Firstly, we observe a poleward migration under a warm, weakened AMOC scenario in the North Atlantic in comparison to the fixed AMOC scenario. These results complement previous studies (e.g., refs 39–42) that find that anthropogenic forcing yields a poleward shift of TC activity, but pinpoint the role of AMOC weakening in this shift. We also observe an increase in GPI near the Western coast of Africa, the Northeastern coast of Australia, and near coastlines in the Arabian Sea and the Bay of Bengal in a warmer climate with a weakened AMOC

Perhaps most strikingly, we find that in the North Atlantic basin, a weakened AMOC in a warmer climate yields a strong increase in GPI along the eastern coast of the U.S. and in the Gulf of Mexico, which has significant socio-economic implications for future storm planning in populated regions along the coastal U.S. In contrast, the North Atlantic TC main development region exhibits a slight decrease in GPI.

Figures 3b. and 3c. illustrate the impact of a weakened AMOC on two key variables that constitute the GPI formula (Eq. 1) – potential intensity (PI) and vertical wind shear (also see Extended Data Fig. 1). First, in the North Atlantic with a weakened AMOC, we observe an increase PI above 15°N. A notable increase in PI along the U.S. eastern coastline corresponds to regions of increased GPI in the scenario with a weaker AMOC.

Similarly, in the Indian Ocean, along the northern coastline of Australia, and in the Western North Pacific basin near the coastlines of the Philippines and Vietnam, an increase in PI linked to the weakening of the AMOC plays a key role in the GPI increase. Also, a decrease in PI in the North Atlantic at latitudes below 15°N, in the Southern Indian Ocean, and in the Southern West Pacific (due to AMOC slowdown) likely contributes to the decrease in GPI in these regions.

Other spatial changes in GPI appear to be governed largely by changes in vertical wind shear (Methods). First, in the NA, we observe that changes in GPI in the TC main development region largely resemble the difference in vertical wind shear under a weakened AMOC scenario. We observe a slight decrease in vertical wind shear along the U.S. coastline, suggesting that a weakened AMOC contributes to a decrease in shear. We also find that a weakened AMOC contributes to an increase in Caribbean vertical wind shear and slight decrease in vertical wind shear off the western coast of Africa, which aligns with the results presented by Yan et al. 2017 (33; see Fig. 3). The increase in Caribbean wind shear, along with the decrease in shear near the U.S. coastline, appear to contribute to the respective slight decrease and increase in GPI in these regions of the basin.

Other spatial changes in global GPI connected to a weakened AMOC in a warm climate are influenced by a combination of variables included in the GPI equation (Eq. 1), such as mid-tropospheric moist entropy deficit and absolute vorticity, but their effects are minor (Extended Data Fig. 1). In summary, in a warm climate with AMOC decline, changes in PI and vertical wind shear affect GPI the most.

Mechanisms for the increase in projected TC activity

We next focus on the mechanisms that determine the impacts of AMOC slowdown on potential intensity and vertical wind shear, especially in the NA. Firstly, given the important relationship between PI and SST (43), to understand the connection between a weakening AMOC and increased PI along the US eastern seaboard, we examine the difference in SST between the two model simulations (Fig. 1c). Most notably, a weakening of the AMOC acts to reduce SST in the subpolar North Atlantic, known as the North Atlantic Warming Hole (NAWH), north of 40ºN. However, we observe only a negligible relative decrease in SST in the NA region where PI increases with a weakened AMOC (roughly between 15 and 35º). Thus, changes in SSTs due to AMOC weakening in the Atlantic Ocean should not have a strong effect on PI in this region.

On the other hand, PI critically depends on air-sea thermodynamic disequilibrium and Carnot efficiency (44). Figure 4 illustrates the difference in air-sea thermodynamic disequilibrium and the modified Carnot efficiency (Eq. 5) due to AMOC weakening. With a weaker AMOC, we observe a relative increase in air-sea thermodynamic disequilibrium (mean values of TC-season air-sea thermodynamic disequilibrium and Carnot efficiency are shown in Extended Data Fig. 5). The observed increase in thermodynamic disequilibrium, for the weakened AMOC, is associated with a stronger relative cooling of the troposphere than the ocean in the subtropical North Atlantic in the wk experiment (Extended Data Fig. 4 and Fig. 1). We emphasize that here we describe a relative cooling (the wk minus fx simulation), since the troposphere actually warms in both experiments. Since the Carnot efficiency does not change much for a weakened AMOC in the regions of interest (Fig. 4b), we conclude that a heightened air-sea thermodynamic disequilibrium is the key factor contributing to a higher PI with a weaker AMOC.

Next, given the potential influence of vertical wind shear on the spatial shift of projected TCs and overall basin-wide TC activity when comparing the two simulations, both of which come from one climate model (CCSM4), we further examine how robust the impact of AMOC decline on global vertical wind shear patterns is across a broader selection of climate models. Specifically, we regress vertical windshear onto the change in strength of the AMOC in RCP8.5 and historical CMIP6 model simulations (Fig. 5). Figure 5 confirms that a decrease in AMOC strength is associated with statistically significant changes in vertical wind shear, particularly in the Atlantic. We find that across the simulations, AMOC weakening is associated with a decrease (increase) in vertical wind shear near the U.S. eastern seaboard (Caribbean and TC Main Develop Region), and these results are in general agreement with our CCSM4 simulations. We note that Fig. 5 also reveals that there is large variability in the magnitude of projected AMOC weakening across different GCMs, as well as in wind shear changes. In our particular climate GCM, changes in wind shear due to AMOC slowdown appear to be generally less important than changes in TC potential intensity.

Impacts of AMOC weakening in a warm climate on TC activity: dynamical downscaling

To confirm the inferences from the GPI analysis and provide an independent assessment of the role of AMOC in TC activity, we turn to downscaling TC tracks for the wk and fx simulations for the period 2075–2100 as depicted in Fig. 6. The downscaling model makes use of large-scale variables from the GCM simulations to propagate seeded atmospheric vortices while estimating their evolving amplitude (Methods). A relatively small fraction of imposed “seeds” develops into tropical cyclones and is used in the analysis.

Critically, Fig. 6b reveals a greater TC track density in the North Atlantic in the wk simulation in comparison the fx simulation, which is consistent with increased GPI values along the U.S. coastline is the experiments with a weakened AMOC (Fig. 3). We also observe an increase in track density with a weakened AMOC in the Southern Indian Ocean, Western South Pacific, and in the Western North Pacific near the coast of Japan. These results generally agree with GPI predictions, even though there are some differences (notably in the Western North Pacific and north Australian regions).

Furthermore, we find that AMOC slowdown in a warm climate contributes to TC poleward migration (42) in the North Atlantic since AMOC slowdown appears to trigger more high latitude TC activity in the North Atlantic.

Climate models give a range of projections for the future impacts of anthropogenic warming on global TC activity (7–21). Additionally, although climate models agree that global warming will lead to the weakening of the AMOC, the exact slowdown rate of this ocean circulation system remains uncertain (23, 29, 30, 36). A few studies (33–35) have found possible links between the strength of the AMOC and TC activity, particularly in the Atlantic Ocean, but to the best of our knowledge, none have systematically examined the impact of a weakened AMOC on global TC activity in a warmer late-21st century climate.

Using two future RCP8.5 climate model simulations and controlling the strength of the AMOC (Figs. 1a and 1b), we find that AMOC slowdown in a warming climate alters GPI change. In fact, AMOC weakening enhances projected increases in GPI in many locations. Most notably, our models show that in the late 21st century with a weakened AMOC, GPI increases in the Caribbean and near the southeastern U.S. (Fig. 3). These results have important implications for TC risks for these densely populated coastal communities (3–6, 45).

We further find changes in PI and vertical wind shear are critical in driving the projected changes in TC activity in a warm climate with a weakened AMOC. We note that in a global warming scenario with a weakened AMOC, large increases in potential intensity in the NA contribute to the overall enhancement of TC activity (Fig. 3). Therefore, we examined two key terms that comprise PI (Fig. 5) and find that with a decline in the AMOC strength there is an increase in air-sea thermodynamic disequilibrium driven by a relative cooling of the troposphere (Extended Data Fig. 4). This atmospheric temperature reduction caused by AMOC slowdown in a warm climate contributes to more favorable TC genesis conditions as reflected by greater air-sea thermodynamic disequilibrium, a higher PI and hence GPI.

Furthermore, we find that a decline in the AMOC strength has important implications for vertical wind shear, which govern some of the spatial shifts in global TC projections (Fig. 3). Specifically, in our controlled model experiment we observe that in a warm, late-21st century climate with a weakened AMOC, as opposed to a warm climate with an artificially fixed AMOC, vertical wind shear decreases near the southeastern U.S. seaboard, which yields favorable conditions for TC development as reflected by a relatively higher GPI.

To add robustness to these results, we regress the change in vertical wind shear between the weakened AMOC warm simulation and the artificially fixed AMOC simulation across 19 CMIP6 historical and RCP8.5 model simulations (Fig. 4). Here, we similarly find that the models project that a decrease in the AMOC strength is significantly associated with a decrease (increase) in shear near the U.S. coastline. Yan et al. (2017) regressed shear onto a weakened AMOC in the Atlantic basin over the observational record and found similar results. These results also align with previous studies to show that in global warming scenarios, TC main development vertical wind is projected to increase (46) and that there is a notable inverse relationship between main development region shear and favorable TC conditions closer to the U.S. eastern seaboard. We note however that the increase in potential intensity in the NA appears is the dominant effect in strengthening tropical cyclogenesis along the US East coast in our model.

Lastly, we downscale TC tracks from both model simulations to directly observe the impact of a weakened AMOC on future TC density (Fig. 6). We find that a weakened AMOC contributes to an increase in TC track density near the U.S. eastern coastline, which agrees with GPI predictions. We find similar agreement between changes in GPI and track density in a weakened AMOC scenario in the Southern Hemisphere basins, even though there are a number of differences (over the western North Pacific and northern Australia). Thus, directly computing synthetic TC tracks from the wk and fx simulations confirm that a weakened AMOC is indeed an important regulator of TC poleward migration. Therefore, predicting future changes in AMOC is critical to accurately assess the effect of anthropogenic warming on TCs.

Experimental set-up

This study utilizes the NCAR CCSM4 model, a fully coupled climate model that combines the Community Atmosphere Model version 4 (CAM4), the Community Land Model version 4 (CLM4), the sea ice component version 4 (CICE4), and the Parallel Ocean Program version 2 (POP2), with a ~ 1° atmosphere and a nominally 1° ocean (47). It is one of the IPCC AR5 models and captures many key features of IPCC AR5 projections. For this study, we examine the mean 2075–2100 ASO and DJF conditions, in the Northern Hemisphere and Southern Hemisphere respectively. Each CCSM4 experiment we use has 5 ensemble members. To estimate the strength of the AMOC, we calculate the maximum of the annual mean stream function below 500 m in the North Atlantic.

To produce an RCP8.5 fixed AMOC simulation (36), “fx”, which is driven by the same radiative forcing as CCSM4 RCP8.5 simulation from 1980 onwards, fresh water is gradually removed from the sub-polar North Atlantic. The varying rate of freshwater removal that allows us to keep the AMOC index nearly constant is determined by successive interactions. In the fx simulation between 1981–2100, variations in the AMOC strength are 0.000 ± 0.003 Sv/year (insignificant with 95% confidence based on the Mann-Kendall trend significance test). This is compared to the other CCSM4 RCP8.5 simulation, wherein the AMOC declines at a rate of − 0.073 ± 0.003 Sv/year (significant with 95% confidence based on the Mann-Kendall trend significance test). Surface freshwater fluxes for both model simulations are discussed in the Materials and Methods section of Liu et al. 2020.

In addition, we calculate the maximum AMOC strength between 20°N and 80°N for each of the 19 CMIP model historical (1980–2005) and RCP8.5 (2075–2100) simulations.

GPI and relevant TC metrics

Several TC metrics are computed from the CCSM4 model simulations as described below. The tropical cyclone genesis potential index (GPI; 48) is calculated using the following equation (Emanuel, 2010):

$$\:GPI=\:{\left|vort\right|}^{3}\:\times\:\:{\chi\:}^{\frac{-4}{3}}\:{\:\times\:\:MAX\left[\left(PI-35\:m{s}^{-1}\right),0\right]}^{2}\times\:\:{\left[25\:m{s}^{-1}+shear\right]}^{-4},$$

where $\:vort$ represents the absolute vorticity of the flow at 850hPa, and shear is the magnitude of vertical wind shear wind (m s^− 1) between 850 and 250hPa. χ is the moist entropy deficit in the middle troposphere defined as

$$\:\chi\:=\:\frac{{s}_{b}-\:{s}_{m}}{{s}_{s}^{*}-\:{s}_{b}}$$

where $\:{s}_{b}$, $\:{s}_{m}$and $\:{s}_{s}^{*}$ are the moist entropies of the boundary layer and middle troposphere, and the saturation moist entropy at the sea surface, respectively. Moist entropy $\:s$ is approximately defined as

$$\:s=\:{c}_{p}lnT-\:{R}_{d}lnp+\:\frac{{L}_{v}r}{T}-r{R}_{v}lnH$$

where $\:T$ and $\:p$ are temperature (K) and pressure, $\:{c}_{p}$ is the specific heat capacity of air at constant pressure, $\:{L}_{v}$ is the latent heat of vaporization, $\:r$ is the water vapour mixing ratio, $\:{R}_{v}$ and $\:{R}_{d}$ are the gas constants for water vapor and dry air, respectively, and $\:H$ is the relative humidity. Throughout this study the GPI is calculated using monthly mean values of the relevant variables. Following Emanuel (2010) (48), the GPI is normalized to give a global mean value of 90 annual storms over the early 1980–2005 in the wk simulation. The same normalization constant is then used across the entire wk and fx simulations.

Tropical cyclone potential intensity (PI) in Eq. (1) is the largest theoretical speed of TC circular winds assuming the storm is modeled as a Carnot heat engine. As derived by Bister and Emanuel, 2002 (49), PI evaluated at the radius of maximum winds ($\:m$) can be computed as

$$\:{PI}_{m}^{2}=\:\frac{{T}_{s}}{{T}_{0}}\frac{{C}_{k}}{{C}_{D}}({CAPE}^{*}-CAPE)\left|\begin{array}{c}\\\:m\end{array}\right.$$

where $\:{T}_{s}$ and $\:{T}_{0}$ are the temperatures (K) at the sea surface and at the TC outflow branch in the upper troposphere, $\:{C}_{k}$ and $\:{C}_{D}$ are the exchange coefficients for enthalpy and momentum, $\:{CAPE}^{*}$ is the convective available potential energy of air lifted from saturation at sea level in reference to the environmental sounding, and $\:CAPE$ is that of boundary layer air. A different representation of PI (50) yields,

$$\:{PI}^{2}=\:\frac{{C}_{k}}{{C}_{D}}\:\times\:\frac{({T}_{s}\:-{T}_{0})\:}{{T}_{0}}\:\times\:{(k}_{s*}-\:k)$$

where $\:{k}_{s*}$ is the saturation moist enthalpy of air right at the ocean surface and k is the moist enthalpy of air in the boundary layer overlying the surface. Using this equation, we can intuitively decompose potential intensity into an exchange coefficient ($\:\frac{{C}_{k}}{{C}_{D}}$), the modified Carnot efficiency ($\:\frac{{T}_{s}\:-{T}_{0}\:}{{T}_{0}}$), and the air-sea thermodynamic disequilibrium ($\:{k}_{s*}-\:k$). We use Eq. (4) to compute PI and deduce the thermodynamic disequilibrium term as a residual.

In computations, we focus on TC active seasons in both hemispheres, i.e. August to October (ASO) for the Northern Hemisphere and December to February (DJF) for the Southern.

Dynamical Downscaling

We refer to references (7), (51), and (52) for details of the TC downscaling TCs from coarse-resolution global climate models. Briefly, GCM data is used to produce a global climatology for the vertical profiles of temperature, atmospheric humidity and winds. We then create synthetic hurricane tracks. In order to increase track variations, self-consistent random realizations of the winds are created using the means, variances and covariances of daily winds from the GCM simulations. Weak vortices with wind speeds less than 25 kt (1 kt $\:\approx\:$ .51 ms⁻¹) are seeded throughout the tropics randomly in time in space and their motion is computed using a model describing advection by the vertically averaged winds, corrected for a b-drift.

This seeding tapers off near the equator to prevent storm formation in this region. The seeded storm intensities are calculated using a quasi-balanced axisymmetric ocean-atmosphere model (53, 54). Seeds are discarded if within 2 days of the model initiation, wind intensity is < 7 ms^− 1. 15,600 storm tracks were created globally for the wk and fx simulations. We used the dynamical downscaling method for one ensemble member of the wk and fx simulations.

Data Availability

Most of the data utilized in this study are publicly available. All data used to evaluate the conclusions in the paper are present in the paper. Additional data related to this paper may be requested from the authors. Data from the CCSM4 model is available at https://www.cesm.ucar.edu/models/ccsm4.0/ccsm/. CMIP6 data utilized for the regression in Figure 8 (monthly zonal and meridional winds, as well as meridional ocean circulation strength) was taken from 19 modeling centers and are available at https://esgfnode.llnl.gov/search/cmip6/. The downscaled hurricane track data analysis software is freely available for research and education purposes only and may be obtained by contacting Dr. Kerry Emanuel at [email protected]. Recipients will be asked to sign a non-redistribution agreement.

Acknowledgements

This study has been supported in part by grants from the National Science Foundation (AGS-2053096 and OCN-1756658). EL was supported by the Barry Goldwater Fellowship. Additional funding has been provided by MOPGA program (ANR-18-MPGA-0001, France). KE was supported by the National Science Foundation under grant AGS-2202785.

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Atlantic ocean circulation slowdown intensifies tropical cyclones in the North Atlantic

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Abstract

Figures

Introduction

Results

Impacts of AMOC weakening in a warm climate on TC activity: GPI results

Mechanisms for the increase in projected TC activity

Impacts of AMOC weakening in a warm climate on TC activity: dynamical downscaling

Discussion

Methods

Experimental set-up

GPI and relevant TC metrics

Dynamical Downscaling

Declarations

References

Additional Declarations

Supplementary Files

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